Billing Manager?

I was looking around
/usr/local/cpanel/whostmgr/bin
and found a program and found a perl script called billmgr is this possibly a billing system to be integrated, or was integrated at one time or another with whm?

I was looking around
/usr/local/cpanel/whostmgr/bin
and found a program and found a perl script called billmgr is this possibly a billing system to be integrated, or was integrated at one time or another with whm?